For example, Unexamined Japanese Patent Publication SHO 63-171765 for the specification of U.S. Pat. No. 4,725,180 already discloses a handling apparatus of this type. This conventional apparatus has a receiving unit for piling on a receiving plate a required number of signatures (sheets of printed paper, folded sheets of paper) delivered from a printing unit, and a stacking unit disposed below the receiving unit and movable upward and downward. An upward feed plate, which is movable upward and downward, is provided laterally adjacent to the stacking unit. A collecting unit is further disposed above this feed plate.
A small stack of signatures as piled on the receiving plate is transferred onto the stacking unit disposed therebelow. The small stack of signatures on the stacking unit is delivered onto the upward feed plate by a pusher plate and then into the collecting unit upon rising the feed plate. Such small stacks are piled in layers into a large stack within the unit.
However, the conventional apparatus has drawbacks. The apparatus requires much time for downwardly delivering the small stack of signatures from the receiving plate to the stacking unit, pushing the stack onto the upward feed plate and further transport. Stacks of signatures are liable to collapse during transport, and the lowermost of the stacked signatures is susceptible to damage.
Further because the uppermost signature of the small stack is in a free state during the transfer from the receiving plate to the stacking unit, the signature is likely to slip out of place and to be further stacked in this state. When small stacks are piled into a large stack in the collecting unit, the folds of signatures of small stacks become bulky, permitting slippage of signatures or causing jamming during transport. Consequently, signatures will be stacked up with some remaining out of register with the others so as to become soiled, damaged or bent and to result in an impaired quality, and hence problems.
An object of the present invention, which has been accomplished in view of the foregoing situation, is to provide a signature handling apparatus which is adapted to efficiently transport signatures as stacked up from a receiving portion to a stacker and further to another stacker without collapsing and free of damage.